编程练习 将一个字符串中的空格替换为 "%20"

 1 def replace(a):
 2         return a.replace(" ", "%20")
 3 
 4 def replace1(a):
 5         b = ""
 6         for i in range(len(a)):
 7                 if a[i] == " ":
 8                         b += "%20"
 9                 else:
10                         b += a[i]
11         return b
12 
13 if __name__ == '__main__':
14         a = "fsfa fsaf sfsaf"
15         print("origin string:",a)
16         print("after replace:", replace(a))
17         print("after replace1:",replace1(a))